Bleaching compositions



United States Patent Ofiice 3,l57,5l3 Patented Jan. 26, 1965 3,167,513BLEACHING Cfih EQSITIONS Jan Cirirsena Meerkamp van Ernhrien and JanBoldingh, Viaardingen, Netherlands, assignors to Lever Brothers Company,New York, N.Y., a corporation of Maine No Drawing. Fiied Mar. d, 1959,Ser. No. 797,053 Claims priority, application Great Britain Mar. 7, 19587 Claims. (Cl. 252-1ti2) This invention relates to bleachingcompositions, and in particular to detergent bleaching compositions.

Many bleaching compositions, especially detergent bleachingcompositions, contain inorganic per-compounds such as sodium perborateor percarbonate. These percompounds provide a satisfactory bleach whenthe composition is used at the boil, but at lower temperatures theiraction is too slow to be really effective within the normal bleachingtime. Moreover, the amount of oxygen used actually in bleaching israther low in comparison with the total amount of available oxygen.

It is an object of the present invention to provide a more effectivebleach than can be obtained with an inorganic per-compound, such assodium perborate, at both low and higher temperatures.

It has been previously proposed to use bleaching compositions containingan organic per-carboxylic acid, such as for example peracetic acid.Owing to the instability of such compounds, particularly in alkalineconditions such as occur normally in detergent compositions, it has,however, been necessary to prepare them only shortly before use. Onaccount of this, it has not been possible to use them commercially,since bleaching compositions are generally used some time aftermanufacture, especially when they are intended for use in the home.

It has now been found that organic per-carboxylic acids derived frommonoor di-carboxylic acids, and their derivatives such as the acylperoxides, can be made into excellent stable bleaching compositions bycombining them with urea to form adducts or so-called inclusioncompounds.

It is, of course, well known, that urea forms inclusion compounds withvarious organic compounds, such as aliphatic hydrocarbons, alcohols,aldehydes, ketones and acids. It was, however not known that urea alsoexhibits this property with organic per-carboxylic acids and acyl Vperoxides.

It has, moreover, been found that the organic perin inclusion compoundswith urea become stabilised to such an extent that they can be used along time after their preparation. In particular, the per-acids and acylperoxides derived from dicarboxylic acids are not affected by otheringredients normally used in bleaching and detergent compositions.

The present invention, therefore, provides an inclusion compound of ureaand a per-derivative of a straight-chain aliphatic carboxylic acid.

It also provides a bleaching composition containing such an inclusioncompound.

Inclusion compounds in accordance with the present invention may beformed by organic alpha-monopercarboxylic acids containing at least 4carbon atoms in the molecule and by organic per-alpha:omega-dicarboxylic acids containing at least carbon atoms in themolecule. Per-acids containing up to 20 carbon atoms in the molecule maybe used; per-monocarboxylic acids containing from 6 to 10 carbon atomsand per-dicarboxylic acids containing from 10 to 14 carbon atoms arepreferred. Per-acids of this type may be derived from saturatedaliphatic monoor dicarboxylic acids and include, for instanceper-butyric acid, per-valeric acid, per caproic acid, per-heptanoicacid, per-caprylic acid, perpelargonic acid, per-capric acid,per-undecanoic acid, per-lauric acid, per-myristic acid, per-palmiticacid, perstearic acid, monoand di-per-sebacic acids and monoanddi-per-brassylic acids. Per-acids containing substituents such as, forexample, methyl, hydroxy, or keto groups and those containing doublebonds may also be used.

Inclusion compounds according to the invention may also be formed byacyl peroxides derived from aliphatic monoor dicarboxylic acids, inparticular from the acids quoted above. In mixed acyl peroxides,however, one of the groups may be derived from an aliphatic monoordicarboxylic acid having a shorter carbon chain than these acids. Theacyl peroxides have the general formulae:

(1) R.C0.0.0.CO.R'

(2) R.C0.0.0.CO.R".COOH

(3) R.C0.0.0.CO.R.C0.0.0H

(4) R.C0.0.0.CO.R".C0.0.0.CO.R' (5) R.C0.0.0.CO.R".C0.0.CO.R'

in which R and R are aliphatic hydrocarbon groups containing from 1 to19 carbon atoms in a straight chain and R" is a divalent hydrocarbongroup containing from 1 to 18 carbon atoms in a straight chain, with therestriction that either R or R contains at least 3 carbon atoms in astraight chain or R" contains at least 8 carbon atoms in a straightchain. R, R, and R may each be substituted and may contain the same ordifferent numbers of carbon atoms.

Mixtures of peracids and acyl peroxides and mixtures of these substanceswith unconverted monoor dicarboxylic acids or their anhydrides may alsobe used.

The method of preparation of the per-acids and acyl peroxides is not afeature of the invention. Two useful methods of preparing the per-acidsare illustrated, however, in the examples, while the acyl peroxides may,for example, be prepared by the reaction of a per-acid with an acidillustrated by the following equation:

The acyl peroxides are often formed in subsidiary amounts in thepreparation of the per-acids.

The inclusion compounds according to the invention may be prepared bytreating the per-derivatives with urea in any known way for preparinginclusion compounds, for example by mixing them with the urea dissolvedin a solvent such as methanol and isolating the product bycrystallisation or evaporation. The products so obtained are crystallinesubstances having the usual structure of inclusion compounds of urea.

All the products of the invention are very stable, but particularlystable products are obtained if a smallamount of sulphuric acid,preferably (LS-3% by weight of the per-derivative, is added during thepreparation of the inclusion compound. They do not explode or ignitewhen heated or subjected to shock and they do not lose oxygen to anyappreciable extent when kept at room temperature. They may frequently bemixed with other substances without losing their stability. Theirstability is, however, diminished by the presence of alkaline compounds.This diminution is less with per-derivatives of dicarboxylic acids thanwith per-derivatives of monocarboxylic acids and, in particular, theinclusion compounds derived from per-derivatives of di-carboxylic acidsare very stable in the presence of the usual ingredients of detergentcompositions. When brought into contact with water they dissolve easilyand the resulting solutions have excellent bleaching properties both atlow and high temperatures, exceeding those of perborate solutionscontaining the same amount of active oxygen. In addiion, such solutionsshow a much better oxygen efficiency than perborate solutions, i.e. theamount of oxygen used actually in bleaching in Comparison with the totalamount of available oxygen is much higher than with perborate solutions.It is, therefore, easier to appl the exact amount needed for thebleaching operation envisaged and this results in greater economy in theapplication of the products of the invention. The products of theinvention are, moreover, strongly bactericidal, for example againstEscherichia coli and Staphylococcus aureus. 3

When products according to the invention are used in detergentcompositions, these may contain either soap or organic soaplessdetergents such as, for example, alkylaryl sulphonates, alkyl sulphates,fatty monoglyceride sulphates, salts of amides of taurine ormethyltaurine, and salts of esters or ethers of isethionic acid. Theymay also contain alkali-metal carbonates, silicates, sulphates, andphosphates, such as orthophosphates, pyrophosphates, polyphosphates andmetaphosphates, and other conventional ingredients of detergentcompositions such as carboxy-methylcellulose, lather improvcrs,fluorescent brightening agents, anti-tarnishing agents, perfumes and thelike. Inorganic per-compounds such as perborates and percarbonates mayalso be present. They may be in any solid form, such as powders, chips,flakes, bars or tablets.

The amount of inclusion compound to be incorporated in a bleachingcomposition depends on various factors such as the bleaching effectrequired and the nature and concentration of the per-acid in theinclusion compound. Bleaching compositions have been found particularlyuseful in which the amount of inclusion compound corresponds to from0.05 to preferably from 0.3 to 1.5%, by weight of the total composition,of active oxygen.

The invention will now be illustrated by the following examples:

EXAMPLE 1 (a) 50 g. (0.8 mol) of boric acid were mixed with 250 g. (2.45mols) of acetic acid anhydride and heated to 90 C. During the reactionthe temperature increased to 120 C. owing to the heat of reactionevolved. On cooling the reaction mixture, pyroboric acetate was obtainedin a yield of 92% calculated on the amount of boric acid used.

(b) 15.2 g. (0.05 mol) of pyroboric acetate and 28.8 g. (0.2 mol) ofcaprylic acid were mixed with 60 ml. of xylene and heated on a waterbath to about 90 C. until a clear solution was obtained. The xylene andthe acetic acid formed during the reaction were then distilled ofi at atemperature of 3040 C. under a vacuum'of mm. Hg. The residue was acrystalinesolid consisting of pyroboric caprylate, obtained in a yieldof 99% calculated on the pyroboric acetate used.

(c) 12.5 g. (0.02 mol) of pyroboric caprylate were added in about 15minutes to 0.08 mol of hydrogen peroxide dissolved in ether at 10 C. Thereaction mixture was kept at room temperature (about C.) for one hourand the boric acid formed was filtered off. The filtrate was Washed withwater and dried over sodium sulphate and the ether was distilled off atabout 20 C. under a vacuum of 15 mm. Hg. The residue consisted of amixture of per-caprylic acid (about 68%), dicapryl peroxide (aboutcaprylic acid (about 4%) and boric acid (about 3%) obtained in a yieldof 65% of per-compounds calculated on the pyroboric caprylate used. Itis a rather unstable liquid which normally loses practically all itsactive oxygen at room temperature in about 8 days.

(d) 10 g. of this residue were added at room temperature about 20 C.) to50 g. of urea dissolved in 250 ml. of methanol.

The mixture was then cooled to -10 C. and the contaminated urea whichprecipitated was filtered oil. The

filtrate was freed from methanol by evaporation at 40 C. under a vacuumof 15 mm. Hg. The residue (29.5 g.) consisted mainly of the ureainclusion compounds or percaprylic acid and dicapryl peroxide. Itcontained about 18% by weight of the per-compounds. It was very stable;on keeping some at room temperature for 7 days no loss of active oxygencould be detected.

(e) The crude percaprylic acid mixture obtained according to (c)was'fractionated under a vacuum of 15' mm. Hg. In this way practicallypure dicapryl peroxide was obtained. The dicapryl peroxide is a fairlystable crystalline solid, losing about 18% of its active oxygen at roomtemperature in 8 days. It can be converted into the urea inclusioncompound by theprocess given under (d).

EXAMPLE 2 (a) To 39.8 g. (0.2 mol) of lauric acid dissolved in 61.2 g.(0.6 mol) of sulphuric acid (96%) were gradually added 20.5 g. (0.3 mol)of a 50% hydrogen peroxide solution at 10 C. with constant stirring.After the addition, stirring was continued for 3 hours at 15 C. Thesuspension thus obtained was diluted with ice-water, which caused theper-acid to precipitate. The precipitate was filtered off, Washed fourtimes with ice-water and dried in a vacuum desiccator. 39.1 g. of drycrystalline product containing 89% of per-lauric acid were obtained(yield 81%).

(b) 6 g. of per-lauric acid as obtained under (a) and 18 g. of urea weredissolved in 100 ml. of methanol. The solution was heated on a waterbath and the solvent was evaporated under vacuum. 23.9 g. of pureinclusion compound containing 23% of per-lauric acid were obtained.

EXAMPLE 3 (a) To 20.2 g. (0.1 mole) of sebacic acid dissolved in 140 g.(1.2 moles) of sulphuric acid (85%) were gradually added 34 g. (0.3 mol)of a 30% hydrogen peroxide solution at 10 C. with constant stirring.After the addition, stirring was continued for 2 hours at 20 C. Theper-acid precipitated in small crystals and was filtered off, washedfour times with ice-water and dried in a vacuum desiccator. 21.5 g. ofdi-persebacic acid of 96% purity were obtained (yield 88%).

(b) 2.4 g. of urea were mixed with 0.7 g. of di-persebacic acid asobtained under (a). The mixture was heated to 65 C. with vigorousstirring. Without further heating the temperature rose to 70 C. Afterstirring for another 30 minutes, the reaction mass was cooled to roomtemperature. 3.1 g. of urea adduct precipitated, containing 19.3%(calculated: 19.7%) of di-per-sebacic acid. The adduct was not a pureinclusion compound, and contained free di-per-sebacic acid andtetragonal urea together with the hexagonal urea-inclusion compound.

EXAMPLE 4 (a) To 23.4 g. (0.096 mol) of brassylic acid dissolved in 140g. (1.2 moles) of sulphuric acid (85%) were gradually added 20.4 g. (0.3mol) of a 50% hydrogen peroxide solution at 10-15 C. with constantstirring. After the addition, stirring was continued for 6 hours at 20C. The per-acid precipitated in small crystals and was filtered off,washed four times with ice-water and dried in a vacuum desiccator.

Thus 26.5 g. of di-per-brassylic acid of 92% purity were obtained (yield92% (b) 41 g. of urea and 10 g. of di-per-brassylic acid as obtainedunder (a) were dissolved in 200 ml. of methanol. The solution was heatedto 50 C. and subsequently cooled to -17 C. The crystalline precipitateformed was filtered off and dricdin a vacuum desiccator. The productthus obtained was the pure inclusion compound containing 23.8%di-per-brassylic acid (yield 33 g., i.e. 90

EXAMPLE Three detergent compositions were prepared from the followingingredients:

Three solutions were made, each containing 5.4 g. of the above-mentioneddetergent composition dissolved in 1 l. of water (14 German hardness).To these solutions were added sodium perborate, the inclusion compoundof di-per-sebacic acid as prepared in Example 3 and the inclusioncompound of di-per-brassylic acid as prepared in Example 4,respectively, in amounts corresponding to 60 mg. of active oxygen perlitre.

Pieces of cotton stained with tea were washed in these solutions atdifferent temperatures and for different times. The cotton to washingliquid ratio was 1:20. The table below shows the results, expressed asincrease in percent reflection measured with an Elrepho reflectometer.

1. A bleaching composition which contains an inclusion compound of ureaand a per-derivative of a straightchain aliphatic alpha-monocarboxylicacid containing 4 to 20 carbon atoms in an amount sufiicient to imparteifective bleaching properties to the composition.

2. A bleaching composition which contains an inclusion compound of ureaand per-caprylic acid in an amount sufficient to impart effectivebleaching properties to the composition.

3. A bleaching composition which contains an inclusion compound of ureaand per-lauric acid in an amount sufficient to impart effectivebleaching properties to the composition.

4. A bleaching composition which contains an inclusion compound of ureaand a per-derivative of a straightchain aliphaticalpha:omega-dicarboxylic acid containing 10 to 20 carbon atoms in anamount sufficient to impart effective bleaching properties to thecomposition.

5. A bleaching composition which contains an inclusion compound of ureaand di-per-sebacic acid in an amount sufiicient to impart effectivebleaching properties to the composition.

6. A bleaching composition which contains an inclusion compound of ureaand di-per-brassylic acid in an amount sufficient to impart effectivebleaching properties to the composition.

7. A bleaching composition which contains as a bleaching agent aninclusion compound of urea and di-perbrassylic acid in an amountcorresponding to 0.05-10%, by weight of the total composition, of activeoxygen.

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1. A BLEACHING COMPOSITION WHICH CONTAINS AN INCLUSION COMPOUND OF UREAAND A PER-DERIVATIVE OF A STRAIGHTCHAIN ALIPHATIC ALPHA-MONOCARBOXYLICACID CONTAINING 4 TO 20 CARBON ATOMS IN AN AMOUNT SUFFICIENT TO IMPARTEFFECTIVE BLEACHING PROPERTIES TO THE COMPOSITION.